Setting The Seal Adjuster And The Stroke Limiter - GEM 660 Operating Instructions Manual

10 Installation in piping

10.8 Setting the seal adjuster and the stroke limiter

▶ Only set the seal adjuster when the valve is completely
assembled (with diaphragm and valve body) and in a cold
condition.
10.8.1 Setting the seal adjuster
(seal adjuster serves to protect the diaphragm)
1. Move the actuator to the closed position.
2. On the outside of the protective cap A, undo the grub
screw B with a hexagon wrench and remove the protective
cap A.
3. Unscrew the stroke limiter C.
4. Move the actuator to the open position.
5. Unscrew the special bush with the indicator spindle D (do
not pull the indicator spindle out of the special bush).
6. Special note for actuator size 1 (diaphragm size 10):
Undo the nut F of the special bush D.
GEMÜ 660
NOTICE
A
B
C
D
E
7. Move the actuator to the closed position (for the NO and
DA control functions, pay attention to the max. control
pressure specifications).
8. Screw down the hexagon nut C with a ring wrench until it
fits closely to the contact surface of the housing cover G.
9. Depending on the diaphragm size, continue to turn the
hexagon nut E.
10. The values below are approx. reference values which may
be different depending on the local process parameters.
▶ If the hexagon nut E is tightened too much, the diaphragm
lifts off from the sealing weir and the valve leaks down-
stream.
Diaphragm size 8: 1/16 rotation
Diaphragm size 10: 1/8 rotation
Diaphragm size 25: 1/8 rotation
11. Further tightening of the hexagon nut E may increase the
service life of the diaphragm but it must be checked
whether the valve is still leak-tight. Screw the special bush
D into the hexagon nut E (secure the adjustment of the
hexagon nut E).
▶ Ensure that the hexagon nut E does not move while secur-
ing it.
Special note for actuator size 1 (diaphragm size 10):
It is easier to secure the hexagon nut E with the special bush
D if the actuator is moved to the open position. The nut F
must then be secured on the special bush D.
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Actuator size 1
(diaphragm size 10)
F
D
G
NOTICE
NOTICE
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